Tripropellant Rotating Detonation Rocket Engine Systems

ABSTRACT

An improved rocket engine system including a rotating detonation rocket engine, and three propellants. The propellants consist of at least one oxidizer and at least one fuel. A third propellant, a fuel or oxidizer or inert fluid, is injected to control the detonation characteristics. The improved rocket engine system may further include at least one additional rocket engine (pump provides pressure for multiple engines). The improved rocket engine system may further include multiple turbopump shafts for independent control of the propellants.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of provisional patent application No. 63/130,584 filed Dec. 24, 2020 by the present inventor, which are incorporated by reference in their entirety.

FEDERALLY SPONSORED RESEARCH

Nonapplicable.

BACKGROUND

The present invention relates generally to rockets, and rocket engines. More specifically, the present invention relates to improved rotating detonation rocket engine systems with three propellants for improved performance and lifetime.

The Applicant is unaware of inventions or patents, taken either singly or in combination, which are seen to describe the instant invention as claimed.

In rotating detonation rocket engines, the combustion chamber is arranged as an annulus, allowing the detonation wave(s) to travel circumferentially, while propellants are injected axially. Before the detonation wave front reacts the propellants, the mixed propellants often start combusting but at constant pressure (deflagration). To maximize performance, the deflagration must be minimized such that all combustion occurs as detonation.

SUMMARY

The present invention relates to improved rotating detonation rocket engine systems with three propellants. In one embodiment, the propellants include a fuel source and an oxidizer source. The third propellant acts as a coolant and could be another fuel, another oxidizer, or an inert fluid. For example, an inert fluid which may be used as a coolant is water. Rotating detonation engines achieve higher efficiency by reacting the fuel(s) and oxidizer(s) in a constant-volume reaction, resulting in a higher pressure and temperature gain. Distinct from existing rotating detonation rocket engines, the current invention separates the injection of the main fuel and main oxidizer by a third propellant to suppress parasitic deflagration.

One embodiment of the improved rotating detonation rocket engine system includes an inert coolant as a third propellant, with a propellant pressurizing system with a propellant pressurizing source, a heat exchanger, and the pressurization source driven by the coolant after it passes through the rocket engine and heat exchanger (expander cycle). The injection system is three concentric channels. The innermost is the oxidizer, the middle channel is the coolant, and the outer channel is the fuel. In this configuration, the amount of coolant can be adjusted to minimize parasitic deflagration. In another embodiment, this order is reversed, so that the innermost is the fuel, the middle channel is the coolant, and the outer channel is the oxidizer.

BRIEF DESCRIPTION OF THE FIGURES

These and other characteristics of the present invention will be more fully understood by reference to the following detailed description in conjunction with the attached drawings, in which:

FIG. 1 is a detailed schematic view of one embodiment of an improved rotating detonation rocket engine system with an inert coolant as a third propellant according to the present invention, showing a coolant source, fuel source, oxidizer source, pressurization system, and heat exchanger; and

FIG. 2 shows the end-on view of the injector.

DETAILED DESCRIPTION

FIG. 1 is a detailed schematic view of one embodiment of an improved rotating detonation rocket engine system with an inert coolant as a third propellant according to the present invention, showing a coolant source, fuel source, oxidizer source, pressurization system, heat exchanger. In other embodiments, the coolant may be another fuel or another oxidizer.

The rotating detonation rocket engine system uses propellant that includes a fuel source stored in the vehicle and delivered to the engine via the fuel feedline 23, an oxidizer source stored in the vehicle and delivered to the engine via the oxidizer feedline 22, and a coolant source stored in the vehicle and delivered to the engine via the coolant feedline 19 which feedlines are all in communication with a pressurization system 2 consisting of a turbine 15, coolant pump 16, fuel pump 17, and oxidizer pump 18. The coolant pump 16 is in communication with a heat exchanger 11 via a high-pressure coolant line 9. The fuel pump 17 is in communication with the injector 10 through a fuel high-pressure fuel line 7. The oxidizer pump 18 is in communication with the injector 10 through a high-pressure oxidizer line 8.

In one embodiment, the coolant temperature and pressure is increased in the heat exchanger 11 to a supercritical state and then is in communication with the rocket engine via the heat exchanger outlet line 12. In other embodiments, the coolant temperature is increased in the heat exchanger 11 to below a supercritical state. The inner-cowl 5 is cooled by internal coolant channels 4 that are in communication with the heat exchanger coolant outlet line 12 and the hot coolant return line 13. The hot coolant after exchanging heat with the incoming coolant, exits the heat exchanger 11 and enters the coolant turbine 15 via the hot coolant heat exchanger outlet 14. After the coolant provides the power for the pressurization system, the coolant enters the outer cowl 1 via internal coolant lines 21. The outer cowl internal coolant lines 21 cool the outer cowl 1 and are in communication with the injector 10. The injector injects the fuel, coolant, and oxidizer into the combustion annulus 3 where the detonation is established and exits at the throat 6. Details of the injector are shown in FIG. 2. The internal coolant channels 4 and 21 are integrated into the parts via manifolds and passages as those skilled in the art are familiar with.

Referring to FIG. 2, the rotating detonation rocket engine system shows the end-on view of the injector 10 with multiple ports arranged around the annulus with concentric outlets. The oxidizer outlet 27 is in the center, the coolant outlet in the middle outlet 26, and the fuel outlet in the outer outlet 25. It will be apparent to those skilled in the art that oxidizer and fuel may be switched to opposite outlets, and also that other reactive propellants may be used in place of oxidizer and fuel.

CONCLUSION, RAMIFICATIONS, AND SCOPE

The separation of the oxidizer and fuel by the coolant serves to delay the mixing of the fuel and oxidizer thus minimizing the parasitic deflagration, which is a key step in both establishing a rotating detonation, increasing the efficiency of detonation combustion, and increasing engine lifetime. 

What is claimed is:
 1. A rocket engine system comprising: an annular combustion section comprising outer and inner walls, one or more of the walls including one or more cooling passages therein; a first propellant source; a second propellant source; a coolant source containing a coolant; a means of heating the coolant to a supercritical state; a plurality of injection ports arranged around the annulus, each comprising an inner outlet, a middle outlet, and an outer outlet, the outlets arranged concentrically; wherein the first propellant source and the second propellant source are fluidically coupled to the injection ports, one to the inner outlet and the other to the outer outlet; wherein the coolant source is fluidically coupled to the means of heating and the means of heating is fluidically coupled to the one or more cooling passages; and wherein one or more of the means of heating and the one or more cooling passages are fluidically coupled to the middle outlet.
 2. The system of claim 1, wherein the supercritical state corresponds to a temperature and a pressure wherein the temperature is within 10% of the lowest temperature where the coolant becomes supercritical and the pressure is within 10% of the lowest pressure where the coolant becomes supercritical. 